A lot of pineapple on a Caribbean island (7)
I believe the answer is:
grenada
'caribbean island' is the definition.
(I've seen this before)
'a lot of pineapple on a' is the wordplay.
'a lot of' means to remove the last letter (a lot of the word but not all of it).
'pineapple' becomes 'grenade' (pineapple can informally mean a grenade).
'on' is a charade indicator (letters next to each other).
'grenade' with its last letter taken away is 'grenad'.
'grenad'+'a'='GRENADA'
(Other definitions for grenada that I've seen before include "commonwealth state" , "Caribbean country, capital St George's" , "West Indian island" , "Commonwealth country" , "Dare nag go to the West Indies?" .)